Myocardial infarction (formation of an infarct or an area of dead heart muscle) occurs when the blood supply to the heart is interrupted, which can be the result of occlusion (blockage) of a coronary artery, such as follows the rupture of vulnerable atherosclerotic plaque. Acute myocardial infarction (AMI) occurs as the result of sudden blockage of blood supply to the heart. Irreversible death of heart of heart muscle begins to occur if the blood supply is not re-established quickly enough (e.g., within 20 to 40 minutes).
If impaired blood flow to the heart lasts long enough, heart cells die, via necrotic and/or apoptotic cellular pathways, do not grow back and a collagen scar forms in their place. This can result in permanent damage to the heart and scar tissue also puts the patient at risk for potentially life threatening arrhythmias, and/or may result in the formation of a ventricular aneurysm.
Diseases of the heart, such as MI, are the leading cause of death for both men and women. Coronary heart disease is responsible for 1 in 5 deaths in the U.S. About 1.2 million people in the U.S. suffer a new or recurrent coronary attack every year and of them, approximately 400,000 of them die as a result of the attack.